My first thought would be, as the child is so seriously ill, to use a treatment that is well designed by a professional that can control all the aspects you speak of. We are trying to save her life and her tumor is now controlling her life. This needs to change.
I understand the fear the parents are now in, facing the death of child is the worst experience ever. That I know. Using treatments that work - too late, only gives us temporary hope; you need to act before mainstream medicine damages her.
I will say - the first thing I would do for that child is to get hold of a professional that has been through this with alternative treatments and can help the parents. Using the BX Antitoxin with its history of bringing good outcomes in hopeless cases would be on the top of my list to look at. At Jesicha's Hope there is a page dedicated to the BX Antitoxin and a free consultation is available. This would be a worthy phone call. Leave no stone unturned, this little girl deserves it.